This invention relates generally to interior trim panels for motor vehicles and more particularly to interior trim panels that have a discrete air bag door that is opened by an air bag when it is deployed into the passenger compartment.
These discrete air bag doors are commonly hinged to a retainer or other structural member of the trim panel near one end so that the door pivots open responsive to deployment of the air bag. The opposite or non-hinged end of the discrete air bag door is commonly held down for aesthetic reasons and to prevent tampering such as an accidental or intentional prying up of the unhinged end of the door. This hold down feature is particularly desirable in a top mount arrangement where a large single air bag door is mounted on the top pad of an instrument panel and hinged so that it opens into the windshield. Such an arrangement has an unhinged end near the passengers where it is easily accessed and consequently exposed to a high risk of tampering.
Various releasable hold down devices and constructions have been proposed for the unhinged end of discrete air bag doors.
One example is disclosed in U.S. Pat. No. 4,893,833 granted to Anthony J. DiSalvo and David J. Bauer Jan. 16, 1990 a closure arrangement for an air bag deployment opening in the top pad of an automotive instrument panel that includes a discrete air bag door. The door has an inner supporting layer of aluminum that has a hinging extension at one end that is bolted to a structural support plate underlying the instrument panel. The opposite end of the door is held down by a frangible tab of the door covering of foam and skin that is beneath a lip of the structural support plate of the instrument panel. In a second version, the door has an inner supporting layer of molded plastic that includes an integral hinging flange near one end that is fastened to the air bag canister. The plastic supporting layer of the door also has an integral frangible flange near the opposite end that holds the opposite or non-hinged end of the door down.
U.S. Pat. No. 4,925,209 granted to Hideyki Sakurai May 15, 1990 discloses a front mount arrangement for mounting a discrete air bag door having an aluminum insert formed integrally with the air bag door. The aluminum insert has a hinging extension at an upper end of the door that is bolted to the air bag canister. The lower end of the door is held down by bolts that extend through cut-outs in the lower end of the door covering to clamp the lower end of the door covering between a resilient member and a flange of the air bag canister.
U.S. Pat. No. 5,066,037 granted to Steven Castrigno et al Nov. 19, 1991 discloses another front mount arrangement for an air bag door having an aluminum inner member formed integrally with the air bag door. The lower end of the door is held down by an extension of the aluminum inner member that is held in a releasable latch assembly.
U.S. Pat. No. 5,096,221 granted to Richard Coombs and Scott Rafferty Mar. 17, 1992 discloses an interior trim panel for a motor vehicle having a discrete air bag door with two substrates. The second substrate is riveted to the first substrate to reinforce the door. The second substrate has extensions at each end which define a hinged connection at one end of the door and a releasable connection at the opposite end of the door which are attached to flanges of the reinforcing insert of the interior trim panel for holding the door in place until the air bag is deployed.
U.S. Pat. No. 5,116,079 granted to Richard D. Rhodes, Jr. May 26, 1992 discloses an automotive instrument panel having an integrated air bag door. The lower end of the door skin carries a depending flap that is sewn to an inwardly extending flap of the instrument panel skin to hold the lower end of the door down. The line of stitching forms a frangible tear seam line.
U.S. Pat. No. 5,161,819 granted to Richard D. Rhodes Nov. 10, 1992 discloses a tamper proof air bag door in a top mount arrangement. The unhinged end of the door is held down by hook and loop fastener strips.
U.S. patent application Ser. No. 08/037,337 filed by Mark Guitarini Jun. 7, 1993 discloses top mount arrangements in which the unhinged ends of the air bag doors are held down by cable release mechanisms.
While each of the above air bag door arrangements may be useful for their intended purposes, there is still a need for a simple and efficient device for holding down the unhinged end of an air bag door and releasing it responsive to deployment of the air bag.